{
  "version": "SIU-2026a",
  "print_id": "2026-09-28-frontier",
  "date": "2026-09-28",
  "status": "provisional",
  "basket_costs": [
    {
      "model_id": "claude-sonnet-5",
      "cost_usd": "0.023423"
    },
    {
      "model_id": "gpt-5.1",
      "cost_usd": "0.009087"
    },
    {
      "model_id": "gemini-3.1-pro-preview",
      "cost_usd": "0.041148"
    },
    {
      "model_id": "grok-4.6",
      "cost_usd": "0.017332"
    },
    {
      "model_id": "claude-haiku-4-5",
      "cost_usd": "0.007661"
    },
    {
      "model_id": "gpt-5.4-mini",
      "cost_usd": "0.005260"
    }
  ],
  "weights": {
    "source": "equal",
    "values": [
      {
        "model_id": "claude-sonnet-5",
        "weight": "0.166667"
      },
      {
        "model_id": "gpt-5.1",
        "weight": "0.166667"
      },
      {
        "model_id": "gemini-3.1-pro-preview",
        "weight": "0.166667"
      },
      {
        "model_id": "grok-4.6",
        "weight": "0.166667"
      },
      {
        "model_id": "claude-haiku-4-5",
        "weight": "0.166667"
      },
      {
        "model_id": "gpt-5.4-mini",
        "weight": "0.166667"
      }
    ]
  },
  "dated_siu": "0.01732",
  "exchange_rate_table": [
    {
      "model_id": "claude-sonnet-5",
      "usd_per_siu": "0.0234",
      "spread_to_index": "0.3525",
      "siu_per_usd": "42.6"
    },
    {
      "model_id": "gpt-5.1",
      "usd_per_siu": "0.0091",
      "spread_to_index": "-0.4753",
      "siu_per_usd": "110.0"
    },
    {
      "model_id": "gemini-3.1-pro-preview",
      "usd_per_siu": "0.0411",
      "spread_to_index": "1.3759",
      "siu_per_usd": "24.3"
    },
    {
      "model_id": "grok-4.6",
      "usd_per_siu": "0.0173",
      "spread_to_index": "0.0008",
      "siu_per_usd": "57.6"
    },
    {
      "model_id": "claude-haiku-4-5",
      "usd_per_siu": "0.0077",
      "spread_to_index": "-0.5576",
      "siu_per_usd": "130.5"
    },
    {
      "model_id": "gpt-5.4-mini",
      "usd_per_siu": "0.0053",
      "spread_to_index": "-0.6963",
      "siu_per_usd": "190.1"
    }
  ],
  "sensitivity_block": [
    {
      "policy_variant": "cache-enabled: 40% of T2 input at 10% of input price",
      "dated_siu": "0.01261",
      "delta": "-0.2717",
      "applies_to": [
        "claude-sonnet-5",
        "gpt-5.1",
        "gemini-3.1-pro-preview",
        "grok-4.6",
        "claude-haiku-4-5",
        "gpt-5.4-mini"
      ]
    },
    {
      "policy_variant": "batch-discount: 50% off input and output",
      "dated_siu": "0.008762",
      "delta": "-0.4940",
      "applies_to": [
        "claude-sonnet-5",
        "gpt-5.1",
        "gemini-3.1-pro-preview",
        "grok-4.6",
        "claude-haiku-4-5",
        "gpt-5.4-mini"
      ]
    }
  ],
  "rounding": {
    "dated_siu_sig_figs": 4,
    "basket_cost_dp": 6,
    "usd_per_siu_dp": 4,
    "spread_dp": 4,
    "siu_per_usd_dp": 1,
    "mode": "ROUND_HALF_UP",
    "siu_per_usd_mode": "ROUND_DOWN",
    "notes": "Applied at publication only; all intermediate arithmetic is full-precision decimal. dated_siu rounds to significant figures, not a fixed decimal-place count, so its precision scales with the price rather than being lost as it falls (found live, 2026-09-25 — see docs/methodology.md's Rounding section). basket_cost carries more decimal places than dated_siu needs at any price level so the published print stays reproducible from its own published figures. siu_per_usd truncates so it never overstates the work a dollar buys."
  },
  "cost_of_production_usd": "1.6678",
  "price_snapshot_ref": "price-snapshot-merged-2026-09-28T12-47-27.015Z.json",
  "methodology_version": "v0-draft",
  "methodology_revision": "rules-2026-09-26",
  "series": "frontier",
  "signature": "0x335b2f6b910ae4d1d48a6989471fc294cd7dcee1085912a2e390cd31bc73e197192c8fe9d4c8976a02aa0a139b003b2e9f1ce5782b72cdbd41d5ec0afe69ee60",
  "public_key": "0x030c598ee35bd24b6942e9155bd36c1dbbe77936c700f859e75b0168b0e25cb299",
  "anchor": {
    "chain": "base-sepolia",
    "status": "anchored",
    "tx_hash": "0x2fd2a2de8eace8a9b0c1523ca212b3fa91fab6cca88091ad42b6d75d87884d58",
    "posted_at": "2026-09-28T12:50:46.000Z"
  }
}